Fuel types ?

[Mrp]

Last year (2020) I was lucky enough to change both of my cars out of the family fleet.

The much hated and expensive and uncomfortable 2017 Mercedes E400 Coupe and the much loved 140 Road-sport went to new homes.

I went then to one of the last Performance Pack 7.5 Golf R (de-restricted, big brakes and 310 HP) Jan 2020 registration as a daily instead of the Mercedes.

The petrol recommendation for the Golf was using BP or Shell Plus petrol and I have noticed through experimentation that its performance and economy is better compared with standard Tesco fuel.

When the 420R with RBTB and  Cat delete arrived I continued with standard Tesco fuel not Plus. however when I last used it it was running on the fumes as it went in the garage at home. Tonight I took a petrol can to the garage when I filled up the Golf with its normal BP Plus fuel so I put 10 litres in the can for the Caterham.

So is the map for the Caterhams 420R RBTB sophisticated enough to make use of the extra Octane as clearly the Golfs is ?

I'm interested to know what people think.

Mrp

 

[aerobod - near CYYC]

The 420R / R400D Duratec can not make use of any extra octane on the standard Caterham map due to the absence of a knock sensor with dynamic timing adjustment. Running below the recommended octane can cause knock damage due to too much timing advance for low octane fuel, though. Fuel with a higher octane than the minimum recommended will give a slightly better safety margin over knock, but won't add any power.

[Mrp]

So is the recommended 95, 98, or 99 Octane ?

[Mrp]

Which also brings me to a question I asked went I got the 420R and never got a respose when I added the RBTB as I'm based in Northamptonshire, can Northampton motorsport unlock the Caterham ECU and tweak it to get a bit more performance.

Mrp

[aerobod - near CYYC]

95 RON is listed in the Caterham Handbook as minimum fuel grade (at least the one for my 2012 car).

[Mrp]

Thanks James that is useful information

Mrp

[ChrisC]

Handbook says All models minimum 95 RON.  For some strange reason my Sigma 150 ran with less pops and bangs on Shell Plus, and I fell into the habit of using that for my Caterhams, so I have only run my 420R on Shell Plus. 

Sorry don't know if Northampton Motorsport have the software to modify a locked ECU, but even if they can, they won't be able to unlock it, just modify the map/settings in the locked ECU.  Worth a phone call I guess. 

[Mrp]

Thanks Chris, I never tried my 140 on Plus just ran it on 95 all the time so continued the same with the 420 until I got the Golf, which we got me thinking. I will make the call but was looking for experience from blat chat as far as the remap goes.

VW said that the R would run better on the Plus but 95 was the minimum.

Also given its relationship with the sprint side of the club, I wondered if they had a trick.

Mrp

[Wrightpayne]

My impreza always ran best on Shell v-power and I could tell the difference between that, supermarket uprated fuel and normal 95ron fuel.

The caterham and 911 I cannot tell any difference.

Thats just made me think of putting some in SWMBOs 1.5tsi Octavia, hmmmm...

 

In summary, I think uprated fuels are more noticeable in turbos.

Ian

[mandalman]

off-topic Mrp,  but what did you hate so much about the Merc?  I've just bought a  2019 E400 4matic estate and love it so far. In a different league to my old 2004 E320

[Mrp]

Hi Mandalman

The seats  were ridiculously uncomfortable , literally crippled after an hours journey. It didn't like Northamptonshire roads with potholes it had 14 tyres in 3 years and 36,000 miles and none through wear. Front suspension need a rebuild after 32,000 miles. When I discussed it with Mercedes they basically said TADTS, its the UK roads.

MOT and 4 tyres in August £ 1400 ! all had bulges. One month later blow out on the A14 in Suffolk a wheel and tyre £1300.

I ran it through my company but it was just so expensive to run and bloody uncomfortable.

It was a nice car to look at and a nice engine......but !

The comfort of the Golf and the performance are brilliant, just before the November lock down I came back from Cornwall with only a fuel stop in comfort, something I could not have done in the Mercedes.

Mrp

[mandalman]

understood. The one thing I do truly hate about my E400 are the bloody ridiculous low profile tyres. Absolutely no point in them. My old E320 on normal tyres would cruise over any pothole but I definitely feel them in the E400

 

[StevehS3]

Have to agree with not liking low profile tyres. When choosing spec I go for a smaller rim and higher sidewall where possible. The combination of low profile and runflat is unbearable !

Back on fuel, is it worth using more expensive (which is usually higher octane) fuel for the better quality additives? I can't tell any difference in my standard K but wonder if there are longer term benefits in a cleaner engine and injectors?

[Mrp]

I think its the way they set up the suspension now as well as the Golf has 35 profile tyres but copes with the roads so much better than the Merc did.

Mrp